Electric switch of the mercury tube type



March 6, 1934. I. EYMcc ELECTRIC swrwcn OF THE MERCURY TUBE TYPE Filed July 4, 1928 2 Sheets-Sheet 1 INVENTOR. 1X34 EM"6ABE BY A TTORNEYS.

March 6, 1934. 1. E. MCCABE 1 ELECTRIC SWITCH OF THE MERCURY TUBE TYPE Filed July 4. 1928 2 Sheets-Sheet 2 q- INVENTOR. [RA .51 JW c455 A TTORNEYS.

Patented Mar. 6, 1934 EEEorEIc swrrcn OF THE MERCURY TUBE TYPE Ira E. McCabe, Chicago, Ill.

Application July i, 1928, Serial No. 290,287

% Claims.

This invention relates to improvements in electric switches of the mercury tube type in which there is a mercury to mercury make and break and this application is a continuation or further development of the invention disclosed in applicants prior copending application Serial No. 237,632, filed December 5, 1927 which matured into Patent No. 1,757,436, May 6, 1930.

It is an object of this invention to isolate one of the terminals of the switch in a cup of insulating material adapted to contain a small body of mercury with the other terminal acting as a support for the cup and always in contact with the main body of mercury in a mercury tube switch, so that when the tube is tilted in one direction the main body of mercury will flow into that end, overflow the sides of the isolating cup, make an electrical contact with the mercury contained therein and through the contained mercury to the isolated terminal and when tilted in the opposite direction will flow away from said cup and break the electrical contact through the small body of mercury that remains in the cup and thereby break the circuit through the switch.

While the preferred forms of this invention, as applied to particular forms of mercury tube switches, are illustrated upon the accompanying sheets of drawings, it is to be understood that minor detail changes may be made without departing from the scope thereof.

In the drawings:

Figure 1 is a view in horizontal section, taken on the line 11 of Figure 2, of one form of this invention.

Figure 2 is a view in vertical central section of Figure 1, with parts shown in side elevation, illustrating the switch tube in position just before the electric contact is made.

Figure 3 is a view in side elevation, showing the position of the main body of mercury when the tilting of the tube in the direction shown in Figure 2 has progressed to complete the contact.

Figure 4 is a view in side elevation, showing the tube tilted inthe opposite direction having brok en the contact shown in Figure 3 and-closed a contact at the opposite end through a difierent circuit.

Figure 5 is a view in side elevation of another form of mercury tube switch, showing the contact broken therethrough.

Figure 6 is a view in horizontal section, taken on the line 6-6 of Figure 7.

Figure 7 is a view in side elevation of another application of this invention to a form somewhat similar to that shown in Figure 5.

Figures 8 and 9 are views in side elevation of embodiments of this invention in other shapes of mercury tube switches.

Figure 10 is a view in horizontal section taken on the line 10-10, Figure 11.

Figure 11 is a view in side elevation of a mercury tube switch illustrating an embodiment of this invention in which the current entering and leaving the switch is carried through two separated lead in wires.

Figures 1 to 4, inclusive, illustrate an embodiment of this invention in a two circuit mercury tube switch in which the lead in wires 1, 2 and 3 are arranged in the same vertical plane and out r through the same end of the glass tube 4 which end is thickened and compressed about the wires holding them securely in fixed relation to each other, the opposite end being rounded to close the tube, as is customary in mercury tube switches. The lower lead in wire 1 forms a universal terminal which when the tube is tilted with one end lowermost will be connected by the main body 5 of the mercury to close one circuit through the switch and when the tube is tilted with the other end lowermost the main body 5 of the mercury will flow into the lower end break= ing the first circuit just mentioned and make a connection with the terminal 1 to close another circuit. In this type of switch two similarly formed terminal isolating cups 6 and 6a are provided constructed of insulating material, such as isolantite a refractory are resistant which is readily shaped by molding or machining, having outwardly flaring lips above a circumferential groove and adapted to contain a small body '7 of mercury. The lower lead in wire 1 is bent upward as it leaves the interior of the embracing end of the tube 4, as shown in Figures 2, 3 and 4, then on the arc of a circle to engage in the circumferential groove of the cup 6 nearest that end and then the curved portion is bent towards the bottom of the tube 4 to support the cup at the desired angle and, if desired, an additional cup clamping lead in wire 1a may be welded or otherwise joined to the lead in wire 1, as shown in Figure 1. As the lead in wire 1 departs from engagement ith the first cup 6 it is continued parallel to the bottom of the tube 4 until it approaches the other cup 6a adjacent the other end where it is bent upward at the desired angle and upon'the arc of a circle to engage in the circumferential groove of this cup to support it at the desired angle. The lead in wire 2, next. above, is bent in the manner shown in Figures 2, 3 and 4 upon leaving the interior of the emr ii bracing end of the tube 4 so that its free end terminates within the small body '7 of the mercury contained in cup 6. The uppermost lead in wire 3 is continued after leaving the interior of the embracing end of the tube 4 parallel with the side wall thereof until nearly above the cup 6a adjacent the other end and is there bent downward so that its free end terminates within that cup and is submerged within the small body of mercury contained therein, as shown in Figure 2. It is preferable to encase both lead in wires 2 and 3 for at least the major portion of their length within a glass tube joined integrally with the embracing end of the tube 4, as shown. The cups 6 and 6a are supported by the lower lead in wire or universal terminal 1 at such an angle to the bottom of the tube 4 and to each other that as the tube is tilted during the normal operation of the switch with first one end lower than the other and vice verse. that each cup will retain the small body '7 of mercury submerging the free ends of the other lead in Wires or terminals 2 and 3, respectively, and as the .main body 5 of the mercury flows toward the lowermost end it will flow over the outwardly flared lip of the lower cup without efi'ort and complete the electric contact from the universal terminal 1 through the small body '7 of mercury within that cup to the terminal submerged therein. It is necessary to provide sufiicient mercury in the main body 5 so that when the tube 4 reaches the end of its tilting movement during normal operation the cup at the lower end will be substantially covered or submerged by the main body 5 of the mercury.

By this construction it is seen that the contact is both made and broken as the end of the tube 4 just reaches or just leaves the lower end of its normal tilting movement. As seen by Figures 1 and 2 as the main body of mercury 5 flows toward the depressed end it meets and surrounds the cup 6 and is held by its molecular cohesion from trickling over the lip of the cup until it falls over the lip in a semi-solid body and submerges the cup and its contents, whereby a complete and definite contact is made and maintained as long as the tube 4 remains with that end at the lowermost limit of its tilting movement. Likewise, as the tube 4 is tilted, during its normal operation, in the opposite direction the main body 5 of the mercury departs from the submerged cup in a like manner making a complete and definite break between the universal terminal 1 and the terminal contained in the cup that was submerged by the main body 5 of the mercury. The action is the same in the make and break with the cups at each end irrespective of the rate of travel of the tilting movement during the normal operation of the switch, with both circuits broken until just before the limit of the tilting movement is reached in either direction,

Figures 5, 8 and 9 show an embodiment of the insulating cup 6 isolating the free end of one of the lead in wires or terminals 2 and supported by the other lead in wire or terminal 1, with the isolated terminal submerged within the small body '7 of mercury contained in the cup. While the tubes 8, 9 and 10, respectively, are of unusual contour differing from the customary mercury tube 4, the action of the main body 5 of mercury is the same in each case as the,tubes or bulbs 8, 9 or 10 are tilted during the normal operation of the switch. Figures 6 and '7 show a bulb like mercury tube 11 in which the apex is normally in the position shown. In this case the cup 6 of insulating material is supported by the lead in wire of terminal 1 in a horizontal position and the free end of the other lead in wire or terminal 2 extends into the cup 6. The main body 5 of the mercury normally in the position shown submerges the cup and closes the electrical connection through the switch. Upon swinging the lower end or apex 12 the circuit is broken and upon return to the position shown is again made, the main body 5 of the mercury making and breaking the circuit to and from the smaller body remaining in the cup in the same manner as herebefore described.

Figures 10 and 11 illustrate an embodiment of this invention to increase the current carrying capacity as the passage of such greater current through the customary single lead in wires would heat the same to a degree that would endanger the glass seal thereabout. As shown the tube 13 is provided with thickened pressed together ends 14 and 15. The normal current carrying conductors are divided at each side of the switch and connected to two lead in wires or terminals 16, 16 and 1'7, 1'7, each pair of which are embraced and received in the thickened ends, as shown. The lead in wires 16 are shown to be of one continuous length which is bent back upon itself to embrace and support the cup 6 in the manner shown while both of the free ends of the lead in wires 1'7, 1'7 are bent to enter within the cup 6 and be submerged within the small body 7 of mercury contained therein. The main body of mercury 5 makes and breaks the circuit in the same manner as above described. passing through divided and separated lead in wires which pass in spaced apart relation through the ends 14 and 15 of the tube 13 allows the switch to be employed in a circuit of greater carrying capacity without danger of having the ends of the tube fractured.

What I claim is:

1. An electric mercury tube switch comprising an hermetically sealed tube having double lead in wires sealed in opposite ends, the wires entering through one end passing adjacent the bottom of the tube to angularly support a cup of insulating material at the other end, said cup containing a small body of mercury, the other lead in wires terminating in said cup and within said mercury, and a main body of mercury normally in contact with said cup supporting lead in wires and adapted upon tilting of the tube to make and break a circuit by contacting with and departing from said small body of mercury in said cup.

2. A tilting mercury switch including an enclosing glass envelope, a plurality of more than two leading in wires sealed in the walls thereof, a pair of spaced apart refractory cups Supp rted by one of said wires within the envelope, and a movable pool of mercury adapted upon tilting the switch in alternate directions to alternately close a circuit over the surface or the refractory cup between the supporting wire and another wire.

3. A tilting mercury switch including an enclosing glass envelope, a plurality of more than two leading in wires sealed in the walls thereof, a pair of spaced apart refractory cups supported by one of said wires within the envelope, one of said leading in wires terminating in each cup, and a movable pool of mercury adapted upon tilting the switch in alternate'directions to alternately close a circuit over the surface of the refractory cup between the supporting wire and another wire.

4. A mercury switch comprising an outer envelope, a trap of are resistant material therein, a

In this form, the current accepts body oi mercury havmg a portion coed in said trap, and a shiftable portion making and breaking contact with the portion in the trap, a leading in wire secured in one end of the envelope at all times remaining in contact with the shiftable portion of mercury having an arm there on forming a socket which receives and supports the trap in the opposite end of the envelope, and another leading in wire entering the interior of the trap.

5. A mercury switch comprising an outer envelope, a plurality of traps of are resistant material therein, a body of mercury having a portion confined in each of said traps, and a shiftalole portion making and breaking contact with the portion in the trap, a leading in wire secured in one end of the envelope at all times remaining in contact with the shiftable portion of mercury having arms thereon forming sockets which receive and support the traps in spaced apart relation.

6. A mercury switch comprising an outer envelope, a plurality of traps of are resistant material therein, a body of mercury having a portion confined in each of said traps, and. a shiftable portion making and breaking contact with the por tion in the trap, a leading in wire secured in one end of the envelope at all times remaining in contact with the shdftable portion of mercury having arms thereon to lug sockets which receive and support the traps in spaced apart relation, and other leading in wires enter the interior oi each trap.

7. A mercury switch comprising an outer envelope, a plurality of traps of are resistant material therein, means carried by the envelope and supporting the traps in spaced apart relation from each other and from the envelope, a body of mercury having a portion confined in each of said traps and a shiftable portion making and breaking contact with the portions in the traps, a leading in wire'secured in one end of the envelope in constant contact with the shiitable partion of mercury, and other leading in wires entering the interior of each trap and in contact with the mercury portions therein.

8. A mercury switch including an outer envelope, a protective cup of arc resistant material in said envelope, and a resilient member engaged with the envelope and extending for the greater part of the length thereof, said member having an arm formed with a socketed portion receiving and secured to the cup and supporting the cup out of contact with the envelope.

m E; McCABE. 

